POS1419 CANCER INCIDENCE IN PATIENTS WITH AUTOIMMUNE DISEASES TREATED WITH CYCLOPHOSFAMIDE
Authors: Á. Andreu-Suárez, M. Serrano Warleta, C. De la Puente Bujidos
Journal: Annals of the Rheumatic Diseases (2022)

Background Cyclophosphamide (CYC) is one of the first-line drugs for some serious manifestations of autoimmune diseases [1]. It has been associated with the appearance of a secondary cancer [2]. Several studies showing a higher incidence of cancer in small-vessel vasculitis in relation to CYC treatment have been carried out [3], but there is not much evidence about this complication in other autoimmune diseases. Objectives -Estimating the incidence of cancer in patients treated with CYC for serious manifestations of autoimmune diseases. -Comparing the incidence of cancer in autoimmune diseases treated with immunosuppressants (IS) against the incidence of cancer in the general population. Methods This is a single-center retrospective cohort study. We included patients over 18 years old assessed in outpatient clinics of the Rheumatology service at the Ramón y Cajal Hospital from 1990 to 2018. They had been diagnosed with: diffuse or limited cutaneous systemic sclerosis (dcSSc/LSScl), systemic lupus erythematosus (SLE), vasculitis or others. We divided the patients into two groups; those exposed to CYC throughout the follow-up and those not exposed to it (being treated with other IS). Patients who had an active cancer at the time of starting the immunosuppressive therapy were excluded. A descriptive analysis was carried out. The incidence of cancer was compared to the incidence of cancer in the general population according to the 2020 Spanish Network of Cancer Registries data. A multivariate analysis was subsequently performed. Results Regarding the baseline characteristics of the patients included, there were no significant statistical differences in the sex, median age, and personal history of cancer. There was a bigger percentage of smokers in the non-exposed group. The incidence of cancer was similar y both groups (7.5% vs. 4.1%; p0.211). The cumulative incidence of cancer in our sample was 55.55/1.000 patients (95% CI 32.1-94.6). The standardized incidence ratio was 2.19 (95% CI 3.30-11.92) and it was stratified by sex and age. The bivariate analysis is shown in Table 1. Table 1. Comparison between patients with or without appearance of cancer during the follow-up. Cancer (n 12) No cancer (n 204) P value Male sex 7 (58,33%) 31 (15,19%) 0,001 Age at the time of the study 69,92 (±7,54) 53,88 (±16,75) 0,001 Smoking habit 6 (50%) 45 (22,06%) 0,027 Personal history of cancer 5 (41,66%) 5 (2,45%) &lt;0,001 Treatment with classical IS 1 (8,33%) 49 (24,02%) 0,303 Treatment with cDMARDs 1 (8,33%) 21 (10,29%) 1 Treatment with bDMARDs 1 (8,33%) 8 (3,92%) 0,408 Treatment with corticosteroids 2 (16,66%) 38 (18,63%) 1 Method of administration of CYC Intravenous 7 (58,33%) 78 (38,24%) 1 Oral 0 (0%) 6 (2,94%) 1 Both 0 (0%) 2 (0,98%) 1 Total administered dose of CYC (grams) 7,28 (±2,36) 6,59 (±3,68) 0,626 Regarding the multivariate analysis, the variables that demonstrated a statistically significant association with the appearance of cancer were age at the time of the study (OR 1.18 [1.02-1.36], p 0.024) and personal history of neoplasia (OR 7.86 [1.30-47.47], p 0.010). Conclusion The incidence of cancer in patients with autoimmune diseases treated with CYC is not higher with respect to patients with similar diseases treated with other IS. The increased incidence of cancer is associated with the personal history of cancer and older age. Studies with a larger sample size and prospective studies are necessary to verify these results and determine more clearly the associated risk factors. References [1]Dan, D., et al. (2015). Cyclophosphamide: As bad as its reputation?: Long-term single centre experience of cyclophosphamide side effects in the treatment of systemic autoimmune diseases. Swiss Medical Weekly , 144 . [2]Baltus, J. A. M., et al. (1983). The occurrence of malignancies in patients with rheumatoid arthritis treated with cyclophosphamide: a controlled retrospective follow-up. In Annals of the Rheumatic Diseases (Vol. 42). [3]Kermani, T. A., et al. (2011). Malignancy Risk in Vasculitis. In Therapeutic Advances in Musculoskeletal Disease (Vol. 3, Issue 1, pp. 55–63). Disclosure of Interests África Andreu-Suárez: None declared, Marta Serrano Warleta: None declared, Carlos De la Puente Bujidos Speakers bureau: Nordic, Janssen, Boehringer Ingelheim, Pfizer, Consultant of: Gebro, Nordic, Janssen, Boehringer Ingelheim